The chapter gives several examples of sexual serial killers who incorporated fetishes or partialisms into their killings. Glen Rogers was pushed under water by his red-headed mother. When killing, he targeted red-headed women and their bodies tended to be left in water. Volker Eckert had a fetish linked to women’s hair, and the assaulting of women while touching their hair formed a gateway activity to killing. Jerry Brudos developed a shoe fetish after being punished by his mother for wearing women’s high-heel shoes. This exemplifies high incentive salience being attributed to shoes. Salience then extended to women’s feet, a partialism. Charles Albright developed a fetish for eyes, having had early experience with eyes in the course of taxidermy. Yuri Tsiuman obtained an orgasm while choking a woman wearing black tights. Subsequently, he targeted women wearing black tights. H. H. Holmes shows some characteristics of having a fetish acquired to a skeleton.

Serial lust killing shows features of addiction, and some killers describe themselves as addicted. Comparisons of lust killing with such addictions as gambling, drugs and consensual sex reveal similarities. Following Robinson and Berridge, it is suggested that the motivational process involves dopamine and exhibits sensitization of incentive salience with experience of killing. Lust killing shows several common properties with other addictions: seeking to repeat the first ‘high’, escalation, increased wanting over time, gateway activities (soft drugs → hard drugs;rape → killing), ambivalence in engaging, stress increases the tendency to engage in the addictive activity, a sudden high often followed by an aversive condition, craving and a temporary correction of such feelings as hopelessness, lacking control and powerlessness. The urge to kill can suddenly occupy the conscious mind. Lust killers commonly consume alcohol in association with killing. Comparisons reveal some common properties between lust killing and war-time killing.

Behavioral determinants with the largest effects are often those related to the environments in which behaviors occur. This suggests the merits of a shift in focus of changing behavior at scale away from interventions based on deliberation and decision-making and toward interventions that involve changing cues – physical, digital, social, and economic – in environments. This chapter focuses on changing cues in small-scale physical environments – sometimes known as choice architecture or nudge interventions. Despite attracting much interest, these interventions have been little explored from a theoretical perspective. Exploring the mechanisms by which some of these interventions exert their effects provides a starting point. Examining evidence of three interventions – increasing availability of healthier food options, reducing glass size, and putting warning labels on food and alcohol products – suggests no single theory explains their effects. The mechanisms by which these interventions affect behavior change also necessitate different levels of explanation and demand a theoretical framework that applies at different levels. Recognizing the distinction between model-free and model-based learning and behavior may be central to this. Advancing knowledge on changing behavior by changing environments requires robustly designed field studies to estimate effect sizes, complemented by laboratory studies testing mechanisms to optimize interventions and develop theoretical understanding.